This is a working overview of BDNF, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-23 and is reviewed periodically as new material appears.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
=== Respiratory === The primary cause of respiratory failure in dermatomyositis is interstitial lung disease, resulting from damage to the lung interstitium. This is particularly prominent in patients with anti–MDA5 autoantibodies, who are at high risk of developing rapidly progressive interstitial lung disease. In some people, the condition affects the diaphragm muscle, the lungs directly (through inflammation), or both. This causes difficulty breathing, and dermatomyositis is considered to be a restrictive lung disease in patients with these symptoms. Respiratory symptoms occur in about 40% of people with dermatomyositis, and in these people, the symptoms may slowly progress, contributing to increased morbidity and mortality.
Burning solid fuels such as coal and biofuels in the home for cooking and heating is a dominant global source of PAH emissions that in developing countries leads to high levels of exposure to indoor particulate air pollution containing PAHs, particularly for women and children who spend more time in the home or cooking.
Al-Hijri also urged the "remnants" of armed opposition members to surrender, promising that those who do so will be under the protection of the spiritual leadership and "will not be humiliated or mistreated". There were protests in Jaramana with protestors chanting slogans against president Ahmed al-Sharaa and his government. The Syrian army began withdrawing from Suwayda. A statement by the Syrian Ministry of Defense said the withdrawal came after the army had completed operations against "outlaw groups" in the city. State news agency SANA reported the pullout was in line with the deal reached between the government and Druze religious leaders. On 17 July, following the withdrawal of the Syrian army, Druze fighters reportedly discovered entire houses had been set on fire, families slaughtered inside homes, and looting. Witnesses in Suwayda compared the Syrian government's actions to summary executions. clashes between Bedouin and Druze fighters were also reported in the western countryside of Rif Dimashq Governorate. Clashes resumed in Suwayda after government forces withdrew as Bedouins launched new armed assaults on Druze forces, with the stated goal of releasing Bedouin prisoners of war. A Bedouin commander told Reuters that the ceasefire agreement did not bind his men, but only the forces of President Ahmed al-Shara's administration. According to the commander, his forces are aiming to free the Bedouins who were detained in recent days by the Druze fighters.
Sources: en.wikipedia.org
Alphaprodine was sold under several brand names, mainly Nisentil and Prisilidine. It was most commonly used for pain relief during childbirth and dentistry, as well as for some minor surgical procedures. Alphaprodine has a duration of action of 1 to 2 hours, and 40 to 60 mg is equivalent to 10 mg of subcutaneous morphine. Prodine has broadly similar effects to other opioids, producing analgesia, sedation and euphoria. Side effects can include excessive itching, nausea, vomiting and potentially serious respiratory depression which can lead to life-threatening respiratory arrest. Respiratory depression can be a problem with alphaprodine even at normal therapeutic doses. Unlike pethidine, prodine does not produce toxic metabolites and is therefore more suitable for high-dose therapy.
Congenital abnormalities: Atrial septal defect Aortopulmonary window Ebstein's Anomaly Patent Ductus Arteriosus (PDA) Surgical intervention: Transcatheter closure of a PDA Incidence: due to the close proximity of the LRLN to the aortic arch, transient paralysis can occur in 10% of cases while permanent effects can occur in 1% of cases. This can further be attributed to using metal clips (used to control bleeding) during the surgical procedure and is more common in premature infants. Cardiac disease: Left atrial enlargement due to valvular heart disease Notable case: A middle-aged male had ongoing cough, hoarseness of voice, and shortness of breath for two years without a history of smoking was found to have mitral valve stenosis due to calcification. This led to left atrial enlargement, elevated pulmonary artery pressure, pulmonary artery hypertension, and right ventricular enlargement. This cardiomegaly, or enlargement of the heart, led to compression of the LRLN. Atrial Myxoma Aorta: Traumatic injury Incidence: Although injury to the thoracic aorta is often fatal, in 10% of cases that take longer to present, hoarseness may be the first symptom. Aortic dissection More commonly affects the right recurrent laryngeal nerve as the most common type of aortic dissection is type A (Figure 2). Pseudoaneurysm Notable case: A male with long-standing uncontrolled hypertension and hoarseness of voice attributed to life-long smoking was found to have a pseudoaneurysm of the aortic arch which was compressing the LRLN.
Recurrences of the MFS at the site of surgery have developed in 16% to 57% of patients with a significant proportion (25%–52%) recurring multiple times. In one study, recurrences developed between 2 and 82 months (median 53 months) following primary surgery and metastatic disease developed in 23% of patients within 2 to 77 months (median 10 months) following primary surgery. Recurrent tumors tend to be more aggressive and have a much greater tendency to metastasize than primary MFS tumors. In one study, metastatic disease was detected in 23% of patients and occurred at a median of 10 months (range, 2–77 months) after resection of the primary tumor. In a review of multiple studies, the risk of developing metastases for lower grade MFS (defined in the following section) was <5% and for higher grade tumors was 25–30%. MFS metastasize most commonly to the lungs, bone, and lymph-nodes. Individuals with the epithelioid variant of FBS generally present with a tumor in the limbs; the tumors tend to be somewhat larger, more aggressive, and more likely to metastasize than the tumors in non-variant cases. At least 50% of patients with this variant have developed metastases.
Sources: en.wikipedia.org
During FY2018, the federal government spent $4.11 trillion, up $127 billion or 3.2% vs. FY2017 spending of $3.99 trillion. Spending increased for all major categories and was mainly driven by higher spending for Social Security, net interest on the debt, and defense. Spending as % GDP fell from 20.7% GDP to 20.3% GDP, equal to the 50-year average. During FY2017, the federal government spent $3.98 trillion, up $128 billion or 3.3% vs. FY2016 spending of $3.85 trillion. Major categories of FY 2017 spending included: Healthcare such as Medicare and Medicaid ($1,077B or 27% of spending), Social Security ($939B or 24%), non-defense discretionary spending used to run federal Departments and Agencies ($610B or 15%), Defense Department ($590B or 15%), and interest ($263B or 7%). Expenditures are classified as "mandatory", with payments required by specific laws to those meeting eligibility criteria (e.g., Social Security and Medicare), or "discretionary", with payment amounts renewed annually as part of the budget process. Around two thirds of federal spending is for "mandatory" programs. CBO projects that mandatory program spending and interest costs will rise relative to GDP over the 2016–2026 period, while defense and other discretionary spending will decline relative to GDP.
In Japan, Mochida Healthcare, a subsidiary of Mochida Pharmaceutical, produces a line of body soaps and shampoo under the brand name Collage (コラージュ) that contain miconazole nitrate as their main ingredient.
== Research == Breastfeeding research continues to assess prevalence, HIV transmission, pharmacology, costs, benefits, immunology, contraindications, and comparisons to synthetic breast milk substitutes. Factors related to the mental health of the nursing mother in the perinatal period have been studied. While cognitive behavior therapy may be the treatment of choice, medications are sometimes used. The use of therapy rather than medication reduces the infant's exposure to medication that may be transmitted through the milk. In coordination with institutional organisms, researchers are also studying the social impact of breastfeeding throughout history. Accordingly, strategies have been developed to foster the increase of the breastfeeding rates in the different countries.
Fluorotelomer-based products have been shown to degrade to PFOA over periods of decades; these studies could lead EPA to require DuPont and others to reformulate products with a value over $1 billion.
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.